In the early-morning darkness, my 9-year-old son and 6-year-old daughter stood clutching notebooks, binoculars, and snack bags as they shivered in the brisk April air. A silver truck slowly pulled up to the side of the road. My aunt Joan opened the door, and we piled in and took off for our first sandhill crane count.

Aunt Joan, a bird enthusiast, had for years participated in the annual sandhill crane count in Houston County in southeastern Minnesota. Recently, she had traveled to the Platte River valley in Nebraska, where 80 percent of the world's sandhill crane population gathers to feed and fatten up before they migrate northward to nest. We would be counting cranes from an eastern population. These birds typically make a stopover at Jasper-Pulaski Fish and Wildlife Area in Indiana.

I had moved back home to Minnesota after a decade of living overseas, and was trying to introduce my children to all things Minnesotan. Besides sledding, ice-skating, and winter bonfires, I wanted them to experience the wildlife. The sandhill crane count sounded perfect. As part of an annual Midwestern count organized by the International Crane Foundation, we would collect data on how many sandhill cranes we heard or saw from 5:30 to 7:30 a.m.

We drove to our designated counting site, an old farm bordering the lowlands of the Root River valley. We grabbed lawn chairs out of the back of the truck, along with snacks and, for me, a Thermos of coffee.

Mist from the marshland permeated the air. My children, Malcolm and Emily, skipped along as frogs sang in surround-sound. Then, suddenly, a trill interrupted the chorus. Aunt Joan stopped short. "Listen," she said. "That was a contact call."

Proceeding slowly to respect the cranes' home, we listened for more calls until we reached the edge of the wetlands. There we set up our post. Aunt Joan gave us a brief tutorial on the three main types of crane calls. The contact call, low-pitched and soft, is used for "checking in," because among reeds and tall grass, it can be difficult for the birds to see each other. The unison call of springtime is made by two sandhill cranes, standing near each other, to solidify bonding. The guard call is a warning, either to ward off predators or to announce danger nearby.

Our little group settled in to listen with data sheets ready. A myriad of mallards quacked and flew overhead. Geese rose out of the wetlands, their black silhouettes floating across the pale gray sky. And we began to hear more sandhill cranes. Malcolm pointed out a shadow of a crane, majestic in flight. Throughout the morning we heard contact calls, guard calls, and unison calls.

Several times Emily and Malcolm walked around to listen for birds. Both ended up with wet feet, but Aunt Joan was prepared: Socks were pulled off and extra mittens placed on shivering toes, bringing on a fit of giggles.

The sky gradually turned hues of amber, lemon, and cotton-candy pink over the reedy wetland. The colors danced and merged with the fog swirling upward. We, the observers and uninvited guests, soaked in the nature so easily missed due to tendencies to sleep in and stay indoors.

All the while, Aunt Joan kept track of the type of calls and the time we heard them. So did Malcolm and Emily. Emily's journal contained the following information:

Counting Cranes: April 18

5:30 contact

5:31 contact

5:38 contact

5:40 guard call

5:56 guard call

6:07 unison

6:30 unison

6:40 saw crane

7:20 saw crane

At 7:30 a.m. we packed up and started down the road to Brownsville to meet other birders and turn in our official results. Suddenly, Aunt Joan slammed on the brakes. "I don't believe it!" she exclaimed. "There is a sandhill crane sitting on her nest." She turned to Emily and asked, "How old are you?" Emily replied, "Six." Aunt Joan said, "I am 60, and I have never in all my years seen one on her nest." A red-capped gray bird, with feathers that had been preened with mud, roosted on a grass-covered mound in the middle of a wetland. We couldn't mark it in our official record. But later, when my children asked if we could go again next year, I counted the whole experience as a success.